Conventional methods of quantitative mass analysis using ion trap mass spectrometers require the analyte and corresponding internal standard ions to be injected and analyzed from two time-separated ion injection events. Any fluctuations in the ionization process which occur in between those two ion injection events introduces inaccuracy in the quantitative mass analysis for that particular measurement and subsequently leads to a bigger relative standard deviation (RSD) and uncertainty in such measurements.
What is needed is a quantitative mass analysis method that minimizes or eliminates errors introduced by the fluctuations in the ionization process and improves the uncertainty in the measurement.